Suma de Nodes en una lista enlazada que son mayores que el siguiente Node

Dada una lista enlazada, la tarea es encontrar la suma de todos los Nodes que son mayores que el Node contiguo. Tenga en cuenta que para el último Node de la lista enlazada que no tiene ningún Node al lado, debe ser mayor que el primer Node para que contribuya a la suma.
Ejemplos: 
 

Entrada: 9 -> 2 -> 3 -> 5 -> 4 -> 6 -> 8 
Salida: 14 
9 + 5 = 14
Entrada: 2 -> 1 -> 5 -> 7 
Salida: 9 
2 + 7 = 9 
 

Enfoque: recorra toda la lista enlazada y para cada Node, si el Node es mayor que el siguiente, agréguelo a la suma. Para el último Node, compárelo con el encabezado de la lista enlazada, si el último Node es mayor que el encabezado, agréguelo a la suma. Imprime la suma al final.
A continuación se muestra la implementación del enfoque anterior: 
 

// C++ implementation of the approach
#include <iostream>
using namespace std;
 
// Represents node of the linked list
struct Node {
    int data;
    Node* next;
};
 
// Function to insert a node at the
// end of the linked list
void insert(Node** root, int item)
{
    Node *ptr = *root, *temp = new Node;
    temp->data = item;
    temp->next = NULL;
 
    if (*root == NULL)
        *root = temp;
    else {
        while (ptr->next != NULL)
            ptr = ptr->next;
        ptr->next = temp;
    }
}
 
// Function to return the sum of the nodes
// which are greater than the node next to them
int sum(Node* root)
{
 
    // If there are no nodes
    if (root == NULL)
        return 0;
 
    int sm = 0;
    Node* ptr = root;
    while (ptr->next != NULL) {
 
        // If the node is greater than the next node
        if (ptr->data > ptr->next->data)
            sm += ptr->data;
        ptr = ptr->next;
    }
 
    // For the last node
    if (ptr->data > root->data)
        sm += ptr->data;
 
    // Return the sum
    return sm;
}
 
// Driver code
int main()
{
    Node* root = NULL;
 
    insert(&root, 9);
    insert(&root, 2);
    insert(&root, 3);
    insert(&root, 5);
    insert(&root, 4);
    insert(&root, 6);
    insert(&root, 8);
 
    cout << sum(root) << endl;
    return 0;
}

// Java implementation of the approach
class GFG
{
 
// Represents node of the linked list
static class Node
{
    int data;
    Node next;
};
 
// Function to insert a node at the
// end of the linked list
static Node insert(Node root, int item)
{
    Node ptr = root, temp = new Node();
    temp.data = item;
    temp.next = null;
 
    if (root == null)
        root = temp;
    else
    {
        while (ptr.next != null)
            ptr = ptr.next;
        ptr.next = temp;
    }
    return root;
}
 
// Function to return the sum of the nodes
// which are greater than the node next to them
static int sum(Node root)
{
 
    // If there are no nodes
    if (root == null)
        return 0;
 
    int sm = 0;
    Node ptr = root;
    while (ptr.next != null)
    {
 
        // If the node is greater than the next node
        if (ptr.data > ptr.next.data)
            sm += ptr.data;
        ptr = ptr.next;
    }
 
    // For the last node
    if (ptr.data > root.data)
        sm += ptr.data;
 
    // Return the sum
    return sm;
}
 
// Driver code
public static void main(String args[])
{
    Node root = null;
 
    root=insert(root, 9);
    root=insert(root, 2);
    root=insert(root, 3);
    root=insert(root, 5);
    root=insert(root, 4);
    root=insert(root, 6);
    root=insert(root, 8);
 
    System.out.print( sum(root) );
}
}
 
// This code is contributed by Arnab Kundu

# Python3 implementation of the approach
import math
 
# Represents node of the linked list
class Node:
    def __init__(self, data):
        self.data = data
        self.next = None
 
# Function to root=insert a node at the
# end of the linked list
def insert(root, item):
 
    ptr = root
    temp = Node(item);
    temp.data = item;
    temp.next = None;
     
    if (root == None):
        root = temp;
    else:
        while (ptr.next != None):
            ptr = ptr.next;
        ptr.next = temp;
     
    return root
 
# Function to return the sum of the nodes
# which are greater than the node next to them
def sum(root):
 
    # If there are no nodes
    if (root == None):
        return 0;
 
    sm = 0;
    ptr = root;
    while (ptr.next != None):
 
        # If the node is greater than the next node
        if (ptr.data > ptr.next.data):
            sm += ptr.data;
        ptr = ptr.next;
 
    # For the last node
    if (ptr.data > root.data):
        sm += ptr.data;
 
    # Return the sum
    return sm;
 
# Driver code
if __name__=='__main__':
    root = None;
    root = insert(root, 9);
    root = insert(root, 2);
    root = insert(root, 3);
    root = insert(root, 5);
    root = insert(root, 4);
    root = insert(root, 6);
    root = insert(root, 8);
 
    print(sum(root))
     
# This code is contributed by Srathore

// C# implementation of the approach
using System;
 
class GFG
{
 
// Represents node of the linked list
public class Node
{
    public int data;
    public Node next;
};
 
// Function to insert a node at the
// end of the linked list
static Node insert(Node root, int item)
{
    Node ptr = root, temp = new Node();
    temp.data = item;
    temp.next = null;
 
    if (root == null)
        root = temp;
    else
    {
        while (ptr.next != null)
            ptr = ptr.next;
        ptr.next = temp;
    }
    return root;
}
 
// Function to return the sum of the nodes
// which are greater than the node next to them
static int sum(Node root)
{
 
    // If there are no nodes
    if (root == null)
        return 0;
 
    int sm = 0;
    Node ptr = root;
    while (ptr.next != null)
    {
 
        // If the node is greater than the next node
        if (ptr.data > ptr.next.data)
            sm += ptr.data;
        ptr = ptr.next;
    }
 
    // For the last node
    if (ptr.data > root.data)
        sm += ptr.data;
 
    // Return the sum
    return sm;
}
 
// Driver code
public static void Main(String []args)
{
    Node root = null;
 
    root = insert(root, 9);
    root = insert(root, 2);
    root = insert(root, 3);
    root = insert(root, 5);
    root = insert(root, 4);
    root = insert(root, 6);
    root = insert(root, 8);
 
    Console.Write( sum(root) );
}
}
 
// This code contributed by Rajput-Ji

<script>
 
// Javascript implementation of the approach
 
// Represents node of the linked list
class Node {
        constructor() {
                this.data = 0;
                this.next = null;
             }
        }
         
// Function to insert a node at the
// end of the linked list
function insert( root, item)
{
    var ptr = root, temp = new Node();
    temp.data = item;
    temp.next = null;
 
    if (root == null)
        root = temp;
    else
    {
        while (ptr.next != null)
            ptr = ptr.next;
        ptr.next = temp;
    }
    return root;
}
 
// Function to return the sum of the nodes
// which are greater than the node next to them
function sum( root)
{
 
    // If there are no nodes
    if (root == null)
        return 0;
 
    let sm = 0;
    var ptr = root;
    while (ptr.next != null)
    {
 
        // If the node is greater than the next node
        if (ptr.data > ptr.next.data)
            sm += ptr.data;
        ptr = ptr.next;
    }
 
    // For the last node
    if (ptr.data > root.data)
        sm += ptr.data;
 
    // Return the sum
    return sm;
}
 
 
// Driver Code
var root = null;
 
root=insert(root, 9);
root=insert(root, 2);
root=insert(root, 3);
root=insert(root, 5);
root=insert(root, 4);
root=insert(root, 6);
root=insert(root, 8);
 
document.write( sum(root) );
 
// This code is contributed by jana_sayantan.
</script>

14

Complejidad de tiempo : O(n) donde n es el tamaño de la lista enlazada